Web services are a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface that is described in a machine-processable format such as the Web Services Description Language (WSDL). Other systems interact with the Web service in a manner prescribed by its interface using messages, which may be enclosed in a SOAP envelope. These messages can be conveyed using HTTP, and can comprise XML in conjunction with other Web-related standards. Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks.